Methods for separating oil and water

ABSTRACT

The present invention relates to methods for the separation of oil and water, in particular through the action of a polymeric material on oil/water emulsions (including oil-in-water and water-in-oil emulsions).

The present invention relates to methods for the separation of oil andwater, in particular through the action of a polymeric material onoil/water emulsions (including oil-in-water and water-in-oil emulsions).

The separation of oil and water is an established process which,however, suffers from certain limitations. For example, North Sea crudeoil is extracted from undersea deposits as a foamy emulsion that istypically 80% water and may include other impurities like metal ions andunwanted organic compounds. Depending on the nature of any surfactantspresent, the viscosity of the oil, the phase volume of the dispersedwater and its droplet size, current processes may not be able toseparate the oil and water phases. The known processes are also intendedexclusively for land based operations and hence separation on the seabed or even on the oil platform presents difficulties regarding theavailability of space and sufficiently robust technology capable ofoperating at sub-sea or downhole conditions. The environmental impactand the capital and operating costs of oil extraction can be reduced bysub-sea separation of oil and water. This has the additional benefit ofenhancing the separation process by virtue of a high crude temperaturebefore it is pumped to the oil platform, since by the time it hasreached the platform the crude temperature falls rapidly thus reducingthe ease of separation of oil and water. The integration of oil/waterseparation with produced water treatment can reduce the environmentalimpact of crude oil extraction as well as reducing the capital andoperating costs of crude production.

Other industries where the demulsification and separation of oil/wateremulsions is required include pharmaceutical manufacture, chemicalmanufacture, biotechnology, the nuclear fuel cycle industry and manymore.

Various methods of demulsification and separation have been proposed.Some emulsions can be separated merely by allowing them to settle, butthis generally takes an unacceptably long period of time, sometimes evenseveral years. Spinning or centrifuging can speed up this process, butgenerally not by a great extent.

According to a first aspect of the present invention, there is provideda method for demulsifying and/or separating an oil/water emulsion,wherein the emulsion is contacted with a polymerised High Internal PhaseEmulsion (polyHIPE) material.

According to a second aspect of the present invention, there is provideda use of a polymerised High Internal Phase Emulsion (polyHIPE) materialfor demulsifying and/or separating an oil/water emulsion.

For the avoidance of doubt, the expression “water” as used hereinencompasses all aqueous systems, “oil” encompasses all immiscible withaqueous systems, and “oil/water emulsion” encompasses oil-in-water andwater-in-oil emulsions and other similar emulsions.

The polyHIPE material can be recovered and recycled after the emulsionhas been separated. In addition to the removal of any indigenoussurface-active materials (such as organic carboxylates, asphaltenes,phosphates, oxides and the like) which tend to stabilise emulsions, thepolyHIPE material also removes from the aqueous phase metal ions(including nano-sized organo-metallic clusters) and residualhydrocarbons. Hydrocarbon (including alkyl phenols) concentrationreduction can be further enhanced (to the levels of around 0.5 ppm) bythe use of a hydrophobic form of the polyHIPE material which can also berecovered and chemically treated to re-obtain the starting hydrophobicmaterial. Therefore, the oil-water separation process can be integratedwith production water cleaning (both residual hydrocarbons and metal ionremoval) which can be discharged into, for example, the sea with littleenvironmental impact.

According to a third aspect of the present invention, there is provideda method for the continuous demulsification and/or separation of anoil/water emulsion, wherein the emulsion is contacted with a polymerisedHigh Internal Phase Emulsion (polyHIPE) material and subjected to atleast one further process selected from the group comprising:application of an electric field, application of heat, application ofpressure, flow induced phase inversion, centrifugation, and passageacross a rotating surface.

According to a fourth aspect of the present invention, there is providedan apparatus for demulsifying and/or separating an oil/water emulsion,the apparatus including a component adapted to receive the emulsion andformed of or containing a polymerised High Internal Phase Emulsion(polyHIPE) material.

An integrated demulsification and water cleaning process can be achievedby using existing separation technology (in the form of hydrocyclones).However, for offshore oil-water separation and water cleaning, a novel,intensified process is needed to address the problems of spaceavailability and proximity to the source of the crude oil (i.e., sub-seaor down hole separation and cleaning are desirable). This can beachieved by the intensification of the process using continuousdemulsification and cleaning processes. The intensive demulsificationcan be achieved by utilising the flow induced phase inversionphenomenon. For this purpose, a novel rotating disk contactor (crudeoil-water and demulsifier contact) is proposed where several otherdemulsification fields (such as flow field, electrical field andpressure) can be superimposed. The ultimate aim of these systems is todevelop sub-sea or down hole separation and where needed water cleaning.

The present invention therefore addresses two important problems: thereduction of the environmental impact of crude oil extraction and thesimplification of drilling technology and subsequent down streamoperations by eliminating production water at source and removingsurface active species.

PolyHIPE materials are obtained through the polymerisation of a HighInternal Phase Emulsion (HIPE) in which a continuous phase containspolymerisable components of the emulsion. PolyHIPE materials have amicro-cellular and highly porous structure, and can be produced in theform of particles, powders, fibres (including hollow fibres), monolithicstructures (such as moulded separation modules or shell-and-tube typestructures) or membranes, including hollow fibre membranes and membranesin crossflow filtration configurations. In a typical polyHIPE polymer,styrene or styrene/2-ethyl hexyl acrylate (2-EHA) is used as thepolymerising constituent, but other constituents, for examplestyrene-divinyl benzene, may be used as is well known in the art.PolyHIPE materials are generally initially hydrophobic but may besulphonated, for example by contact with sulphuric acid, to make themhydrophilic. Such sulphonated polyHIPE materials may therefore be usedas ion exchange media which due to their highly open pore structure havea very high rate of ion exchange compared to conventional ion exchangeresins.

Various polyHIPE materials and methods for their manufacture aredescribed in European patent application 0 060 138, the full disclosureof which is incorporated into the present application by reference. Itwill be noted that the polyHIPE materials of EP 0 060 138 are discussedsolely in terms of their ability to retain a liquid, acting rather likesponges.

Some polyHIPE materials which have been investigated by the presentapplicant and methods for the production thereof are described in detailin Akay, G, Bhumgara, Z and Wakeman, R J, Self-supported Porous ChannelFiltration Modules: Preparation, Properties and Performance, Chem EngRes Design 73 (1995) 783-796, the full disclosure of which isincorporated into the present application by reference.

The void volume of the polyHIPE materials investigated by the presentapplicant can be as high as 98%, and the pore size can be controlledaccurately from hundreds of micrometers to fractions thereof, asdescribed for example in the present applicant's International patentapplication WO 00/34454, the full disclosure of which is incorporatedinto the present application by reference.

PolyHIPE materials suitable for use with the present invention may beelastic or rigid depending on the type and proportion of monomers usedin the oil phase of the HIPE, and they may be hydrophobic orhydrophilic.

Suitable polyHIPE polymers may be prepared by using the methodsdescribed in detail in WO 00/34454. The specific properties of polyHIPEpolymers can chosen from a wide range by appropriate manufacturingtechniques and may therefore be tailored to specific applications withrelative ease. Three types of polyHIPE polymer can be used depending onthe surfactant system present in the emulsion to be demulsified andseparated:

1. Hydrophobic (mainly styrene based homo- or co-polymers)—this is thebasic polymer which can be modified to obtain the following ionicco-polymers.

2. Anionic/non-ionic (the degree of each group can be changed).

3. Cationic/non-ionic (the degree of each group can be changed).

These micro-porous polymers can be obtained in bulk or in powder orgranular form. The internal architecture of the polymers can also betailored by controlling the pore size, the interconnecting hole size,the phase volume of the polymer which is usually 5-20% and the secondaryporosity of the walls which can be nano-sized.

The pore size (D) of the polymer can be in the range of 0.5 μm≦D≦500 μmwhile the ratio of the interconnect size (d) to pore size (D) can be inthe range of 0≦d/D≦0.5. Experiments summarised in the presentapplication were conducted using particulate (powder) form with a poresize of D≈10 μm and d≈0.3 μm.

In order to demulsify an oil/water emulsion, all that is necessary is tocontact the emulsion with a suitable polyHIPE polymer. The polymer maybe added in powder or granular form, in which case it has been foundthat the addition of 0.3 g per kilogram of emulsion is effective,although a range of 0.05 g to 5 g of polymer per kilogram of emulsion iseffective, with a range of 0.1 g to 1 g of polymer per kilogram ofemulsion being particularly advantageous. The present applicant hasfound, surprisingly, that the addition of larger amounts of polymertends to slow down the demulsification and separation process. It isbelieved that this is due to the excess polymer absorbing too much waterfrom the emulsion.

Simultaneous demulsification and separation of oil/water phases can beachieved by contacting the emulsion with hydrophobic or hydrophilicsurfaces followed by the removal of oil and water from thedemulsification zone. Demulsification can be enhanced by the applicationof an electric field in which water droplet-droplet contact is enhancedleading to coalescence and subsequent separation under gravity. In bothcases the target phase is the dispersed droplets in which the dropletcoalescence is promoted.

In some embodiments, the intensive demulsification method of the presentinvention targets the removal in the first instance of surface-activematerials present in the emulsion thus causing destabilisation. In orderto achieve this selective removal of the surface-active species, it isadvantageous to use polyHIPE polymers which have both hydrophobic andhydrophilic sites close to each other at a molecular scale. In order toimmobilise the surface-active species, the ‘active’ surface area of themicroporous polyHIPE polymer should be high and accessible. Furthermore,recent studies by the applicant indicate that the behaviour ofsurfactant phases in the nicro-pores of polyHIPE polymers is remarkablydifferent compared with their bulk behaviour, which is believed toexplain why particular types of micro-porous polyHIPE materials are soeffective in the intensification of oil/water separation. Non-porouspolymers with the same chemical structure do not cause any separation.

There is some evidence that microporous polyHIPE polymers createinternal flows due to capillary pressure. The flow effects can also leadto phase inversion, called Flow Induced Phase Inversion in emulsions, asdiscussed by Akay, G, Chem Eng Sci., 53, (1998) 203-223, the fulldisclosure of which is incorporated into the present application byreference. During phase inversion, the emulsion goes through aco-continuous activated state and this may also cause phase separationin the presence of hydrophilic and hydrophobic regions of the polyHIPEpolymer. It is therefore possible to enhance the separation further byusing a continuous flow demulsification process in which an emulsion isforced through a polyHIPE component, for example a membrane, packed bed,hollow fibres etc.

In a continuous oil-water separation process, many of the knownoil-water separation processes can be combined with the demulsificationmethod of the first aspect of the present invention to obtain acontinuous intensified process. Known oil-water separation processesinclude: (i) electric field intensification, (ii) Control DeformationDynamic Mixer (CDDM) technology, (iii) flow induced phase inversion,(iv) high ambient pressure and temperature, and (v) fractionation of oil(including crude oil) during oil-water separation.

Central to this intensified continuous process is the CDDM technology asdescribed by Akay et al. in International patent application WO96/20270, the full disclosure of which is incorporated into the presentapplication by reference. The CDDM can be further modified to have afacility for applying an electric field and in-situ flow induced phaseinversion, demulsification and phase disengagement in the presence of amicro-porous polyHIPE demulsifier. When demulsification is to be furtherenhanced, the flow induced phase inversion should not cause theformation of very small oil droplets. Therefore the flow geometry of theCDDM is important in achieving a phase inversion in the presence ofmicro-porous polyHIPE demulsifier.

Since the efficiency of the polyHIPE demulsifier is dependent on theemulsion type (most probably due to the viscosity of the oil phase) itmay be possible to fractionate the oil at the oil-water separationstage. In all cases, powdered or granular demulsifier can be mixed withthe crude oil emulsion at high pressure by dispersing the powder orgranules into an organic phase (light crude, for example). Injection ofthe demulsifier can be at several suitable points in the process stream.

Embodiments of the present invention are particularly suited to thedemulsification of interfacial crud (IFC) in the nuclear energy andreprocessing industries.

In the reprocessing of spent nuclear fuel, recovery of fissionablematerials, mainly uranium and plutonium, is performed by solventextraction. Among existing processes, the most widely used is the PUREXprocess or thermal oxide reprocessing (THORP), in which the spent fuelis dissolved in 3M to 6M nitric acid. Dissolved heavy metals areextracted using an organic solvent, usually a 30% (by volume) solutionof tri-n-butylphosphate (TBP; extractant) in normal paraffin hydrocarbon(diluent), n-dodecane or odourless kerosene (OK; mainly dodecane withother alkanes C_(n)H₂₊₁; 9≦n≦12).

In the PUREX process, both the extractant and the diluent are graduallydegraded to radiolysis products, including surface active materialswhich then form emulsions. These emulsions can be identified when theextractant and diluent mixture is allowed to rest, the emulsionsappearing at the interface between the organic and aqueous phases. Theseemulsions are referred to as interfacial crud (IFC) which can alsocontain colloidal solids. IFC is thought to be either a water-in-oil oran oil-in-water emulsion, but may also be a multiple emulsion such as(oil-in-water)-in-oil and/or (water-in-oil)-in-water. Although theamount of IFC generated tends to be small, it nevertheless causesproblems in the extraction of fissionable products due to decreased masstransfer and clogging of extraction and transport equipment. Foreffective operation of the PUREX process, it is therefore desirable toprevent the formation of IFC or to break down any IFC formed. IFC may beskimmed off or otherwise removed before or during the solvent extractionprocess and taken to a separate container or the like wheredemulsification and/or emulsion separation may take place.Alternatively, demulsification and/or emulsion separation of the IFC maytake place at the same time as the solvent extraction process.

According to a fifth aspect of the present invention, there is provideda method for demulsifying and/or separating an interfacial crud emulsiongenerated during the reprocessing of nuclear fuel, wherein the emulsionis contacted with a polymerised High Internal Phase Emulsion (polyHIPE)material.

According to a sixth aspect of the present invention, there is provideda use of a polymerised High Internal Phase Emulsion (polyHIPE) materialfor demulsifying and/or separating an interfacial crud emulsiongenerated during the reprocessing of nuclear fuel.

According to a seventh aspect of the present invention, there isprovided a method for the continuous demulsification and/or separationof an interfacial crud emulsion generated during the reprocessing ofnuclear fuel, wherein the emulsion is contacted with a polymerised HighInternal Phase Emulsion (polyHIPE) material and subjected to at leastone further process selected from the group comprising: application ofan electric field, application of heat, application of pressure, flowinduced phase inversion, centrifugation, and passage across a rotatingsurface.

According to an eighth aspect of the present invention, there isprovided an apparatus for demulsifying and/or separating an interfacialcrud emulsion generated during the reprocessing of nuclear fuel, theapparatus including a component adapted to receive the emulsion andformed of or containing a polymerised High Internal Phase Emulsion(polyHIPE) material.

PolyHIPE materials suitable for use with these, as well as theforegoing, aspects of the present invention may have a void volume ashigh as 98% with pore sizes in the range of hundreds of micrometres downto fractions of micrometres. The polyHIPE material may be elastic orrigid depending on the type and proportion of monomers used in the oilphase. The polyHIPE materials may be hydrophobic or hydrophilic. In onepreferred embodiment, a continuous oil phase of a High Internal PhaseEmulsion for the production of a rigid polyHIPE material is made from amixture of styrene with divinyl benzene (DVB) as a cross-linking agentand a water-in-oil emulsifier (surfactant) Span 80. A typical oil phasecomposition is styrene 78%, divinyl benzene 8% and Span 80 14% (all byvolume). For an elastic polyHIPE material, the oil phase may comprisestyrene 15%, 2-ethyl hexyl acrylate (2-EHA) 60%, divinyl benzene 10% andSpan 80 15% (all by volume). The dispersed aqueous phase may comprise asolution of polymerisation initiator, potassium persulphate (0.5% bymass), in double distilled water.

In order to produce a typical polyHIPE material, sufficient quantity ofaqueous phase is dosed into the stirred oil phase until an aqueous tooil phase ratio of 90:10 (by volume) is achieved, over a period of about10 minutes to form a HIPE. The HIPE may be stirred for a further periodof time, e.g. 20 minutes, before being poured into a mould or the like.The HIPE may then be polymerised in an oven at 60° C. overnight tobecome polyHIPE and then dried, before being cut into appropriatelysized pieces (e.g. 1 cm cubes). The polyHIPE pieces may be washed freeof surfactant with isopropyl alcohol or the like and water, and thenre-dried.

PolyHIPE may be sulphonated so as to make it hydrophilic. The polyHIPEpieces may be soaked in 98% (by mass) concentrated sulphuric acid attemperatures of 20 to 90° C. for varying times so as to achieve varyingdegrees of sulphonation. The pieces may then be washed free of excessacid and dried before being subjected to titrimetric analysis in orderto determine the degree of sulphonation. This is possible becausesulphonated polyHIPE becomes acidic as —SO₃ ⁻H⁺ groups become attachedto benzene rings of any crosslinked polystyrene chains present. If thedegree of sulphonation is expressed as a percentage of available benzenerings in the polymer structure which can attain —SO₃ ⁻H⁺ groups, it cantherefore be measured by titrimetric analysis. The hydrophilicity of apolyHIPE material may therefore be tailored to any particularapplication by adjusting the degree of sulphonation.

During sulphonation, the internal porous structure of polyHIPE materialsis etched by the acid, leading to enlargement of the pores and theformation of new, smaller pores within existing cell walls.

It is further to be noted that alkali salts of the polyHIPE material canbe prepared through contact with aqueous alkali solutions after thesulphonation process. This causes an exchange between protons in —SO₃⁻H⁺ groups and positively charged ionic species of the alkalis.

A sodium salt of polyHIPE material (neutralised polyHIPE) may beprepared by soaking polyHIPE samples in, say, 2M sodium hydroxide.

IFC may be demulsified by way of the present invention in either batchor continuous mode.

According to a ninth aspect of the present invention, there is provideda method of demulsifying and/or separating an oil/water emulsion,comprising the steps of:

i) supplying the emulsion to a rotating surface of a rotating surfacereactor;

ii) operating the rotating surface reactor so that the rotating surfacespins at a speed sufficient to cause the solution to spread over therotating surface as a continuously flowing thin film;

iii) contacting the emulsion on the rotating surface with a polymerisedHigh Internal Phase Emulsion (polyHIPE) material so as to causedemulsification and/or separation of the emulsion.

Separated aqueous and organic phases from the demulsified or separatedemulsion may be thrown from a periphery of the rotating surface andcollected, as may the polyHIPE material. The polyHIPE material may beprocessed and recycled.

The emulsion may be a crude oil emulsion, interfacial crud or any othertype of emulsion.

Rotating surface reactors suitable for use with this aspect of thepresent invention are described in the present applicant's co-pendingInternational patent applications PCT/GB0000519, PCT/GB0000521,PCT/GB00523, PCT/GB00/524; PCT/GB0000526 and PCT/GB01/00634, the fulldisclosures of which are hereby incorporated into the presentapplication by reference. Rotating surface reactors may be in the formof spinning disc reactors, spinning cone reactors and other shapedreactors as discussed in the above patent applications.

BRIEF DESCRIPTION OF THE DRAWINGS

For a further understanding of the nature, objects, and advantages ofthe present invention, reference should be had to the following detaileddescription, read in conjunction with the following drawings, whereinlike reference numerals denote like elements and wherein:

FIG. 1 shows SEM micrographs of hydrophobic rigid PHP, magnification500;

FIG. 2 shows SEM micrographs of a S-PHP, magnification 500;

FIG. 3 a shows SEM micrographs of hydrophilic (sulphonated) rigid PHPsoaked in raw crud overnight, a lesser deposited region is shown,magnification 500;

FIG. 3 b shows SEM micrographs of hydrophilic (sulphonated) rigid PHPsoaked in raw crud overnight, magnification 2000;

FIG. 4 shows performance of the original (hydrophobic) rigid PHP in thedemulsification of the crude;

FIG. 5 shows comparison of the demulsification performance of PHP(hydrophobic and hydrophilic) with respect to that of 0.45 μm pore sizemembrane (total demulsification);

FIG. 6 shows PHP washed with methanol and then water after being used indemulsification;

FIG. 7 shows performance of sulphonated (hydrophilic) rigid PHP in thedemulsification of the crude;

FIG. 8 a shows SEM micrographs of the sediments formed in the aqueousphase during the demulsification of crud by hydrophilic PHP,magnification 2000;

FIG. 8 b shows SEM micrographs of the sediments formed in the aqueousphase during the demulsification of crud by hydrophilic PHP,magnification 5000;

FIG. 9 a shows EDAX spectrums of the sediments formed in the aqueousphase during the demulsification of crud by S-PHP-Na;

FIG. 9 b shows EDAX spectrums of the sediments formed in the aqueousphase during the demulsification of crud by S-PHP-Na;

FIG. 10 a shows SEM micrographs of the S-PHP-Na particles remained inthe crud phase after the first demulsification, magnification of aparticle;

FIG. 10 b shows SEM micrographs of the S-PHP-Na particles remained inthe crud phase after the first demulsification, magnification of anotherparticle;

FIG. 11 a shows SEM micrographs of typical remaining crud solidsfollowing demulsification by S-PHP-NA, washed by water;

FIG. 11 b shows SEM micrographs of typical remaining crud solidsfollowing demulsification by S-PHP-NA, washed by ethanol;

FIG. 11 c shows SEM micrographs of typical remaining crud solidsfollowing demulsification by S-PHP-NA, washed by dichloromethanefollowed by hexane;

FIG. 12 a shows EDAX spectrums of typical remaining crud solidsfollowing demulsification by S-PHP-NA, washed by water;

FIG. 12 b shows EDAX spectrums of typical remaining crud solidsfollowing demulsification by S-PHP-NA, washed by ethanol;

FIG. 12 c shows EDAX spectrums of typical remaining crud solidsfollowing demulsification by S-PHP-NA, washed by dichloromethanefollowed by hexane;

FIG. 13 a shows chemical content of some typical crud solids, forpalladium and phosphorous;

FIG. 13 b shows chemical content of some typical crud solids, fornitrogen, carbon and hydrogen;

FIG. 14 a shows SEM micrographs of the hydrophilic PHP particlesremained in the crud phase after demulsification of the remaining crudfrom the first demulsification, magnification 500;

FIG. 14 b shows SEM micrographs of the hydrophilic PHP particlesremained in the crud phase after demulsification of the remaining crudfrom the first demulsification, magnification 2000;

FIG. 15 a shows SEM micrographs of very fine crud particles,magnification 500;

FIG. 15 b shows SEM micrographs of very fine crud particles,magnification 5000;

FIG. 16 a shows EDAX spectrums very fine crud particles, the total areain FIG. 12 a;

FIG. 16 b shows EDAX spectrums very fine crud particles, the bright areashown in FIG. 12 a;

FIG. 17 shows the effect of the degree of the sulphonation for varyingtype of crud and the ratio of mass of PHP to the total volume of initialtube content (M_(PHP)/V_(T));

FIG. 18 shows the effect of S-PHP-Na mass on the aqueous phaseseparation as a function of time;

FIG. 19 shows the effect of the degree of the sulphonation as a functionof time on the demulsification of crud;

FIG. 20 shows the effect of mixture of S-PHP-Na and PHP as a function oftime on the demulsification of crud; and

FIG. 21 shows some typical results of the tests on the treatment ofdegraded solvent phase and spent aqueous phase by commercially availableabsorbent and ion-exchange materials.

For a better understanding of the present invention and to show how itmay be carried into effect, reference shall now be made by way ofexample to the accompanying drawings, comprising FIGS. 1 through to 21.

Batch experiments using powdered polyHIPE demulsifiers with fixedinternal microstructure but varying chemistry and/or solid-surfaceproperties were performed in relation to crude oil emulsions. In theseexperiments two types of emulsions are used. (1) The first type ofemulsion contains, in addition to indigenous surfactants, nano-sizedorgano-metallic particles. (2) The second type of emulsions are based oncrude oils with or without added surfactant. In (1), the kinetics ofemulsification and the mechanism of demulsification were alsoinvestigated in detail. In (2) the mechanism of emulsification is notinvestigated in detail but the demulsification under high pressure hasbeen investigated.

Highly stable water/oil emulsions (50% water) were prepared using aformulation given by industry. The emulsion is stabilised byorgano-metallic nano-particles and indigenous surfactants formed duringthe emulsification process. These emulsions are stable for severalyears. When anionic (either in acid form or Na-salt) microporouspolyHIPE polymer particles are added to this emulsion, the emulsionseparates out upon standing giving three layers within a few minutes(typically 5 minutes). The top layer is the organic phase while thebottom layer is the aqueous phase. The middle layer, depending on theemulsion, can contain unbroken emulsion and/or the polyHIPE polymerparticles. When these particles are analysed, they are found to beheavily filled with organo-metallic particles forming aggregates withinthe pores. The separation efficiency can approach 100% depending on theemulsion and the chemical composition of the micro-porous polyHIPEpolymer. Effective demulsification requires ˜5×10⁻⁴ gram of polymer pergram of emulsion. The location of the polyHIPE demulsifier in theseparated system is dependent on the density of the demulsifier whichcan be controlled as necessary.

Several water-in-crude oil emulsions were prepared using two types offresh crude oil Norsk Hydro). The aqueous phase contained 28.1 g/l NaCl;0.45 g/l CaCl₂; and 5 g/l MgCl₂·6H₂O. Both non-ionic and anionicsurfactants were added if necessary in order to obtain an emulsion whichis stable at least for five days. However, depending on the type ofcrude oil, some of the emulsions are stable for months even without theaddition of emulsifier.

The separation dynamics of some of these emulsions (which separatewithin five days) were studied using static pressure at 200 bar in theabsence or presence of CO₂. It was shown that the pressure acceleratesthe rate of separation by as much as 3 fold, while the presence of CO₂does not have any significant effect. However, the rate of separationslowed down considerably after reaching ˜80% separation within fourdays.

The effect of an electric field on the separation efficiency of thewater-in-crude oil emulsions was also tested. An electric field (at 2kV/cm) had no effect on highly stable emulsions (stable for more thanthree months) but gave approximately 50% separation after 20 minutes forthe samples which yielded 80% separation within four days upon standing.

Even the highly stable emulsions yielded complete separation if ahydrophilic micro-porous polyHIPE polymer was used for demulsification.The demulsification was almost instantaneous and was found to reach upto 100%, and the phase disengagement took place under gravity. The phasedisengagement could be enhanced by using well known techniques afterdemulsification. The efficiency of the phase separation increased withincreasing temperature and decreasing oil phase viscosity. Theseparation efficiency of the process was less than ˜3×10⁻⁴ gram additiveper gram of emulsion.

The oil-water separation with the polyHIPE demulsifier resulted in twolayers. The bottom layer also contained the polyHIPE demulsifier whichcould be separated by filtration and reused. It was possible to ensurethat all of the polyHIPE demulsifier was eventually located in theaqueous phase by ensuring correct density differentiation.

Another important aspect of the present technique was that the residualtotal organic carbon (TOC) in the aqueous phase was also reduced by afactor of 7 compared with gravity separation at atmospheric pressure.

TOC could be further reduced to insignificant levels by treating theaqueous phase with hydrophobic microporous polyHIPE polymer which couldlater be recovered and chemically changed to form the hydrophilicversion for use as the demulsifier. The surface chemistry of thehydrophobic demulsifier could be changed to increase the selectivity inorder to remove more toxic components from the residual oil in thewater. Furthermore, heavy metal ions were also reduced during thedemulsification process. Therefore, the aqueous phase could bedischarged into the sea. The table below gives the TOC and metal ionconcentrations (Mg and Ca) after various types of treatment.

With reference to the demulsification and/or separation of IFC, a modelIFC was prepared and subjected to demulsification in both batch andcontinuous modes.

Batch mode demulsification was performed in measuring cylinders of 50 mlcapacity. Predetermined volumes of the model IFC samples were taken froma well shaken stock bottle into the cylinder, which will be referred asa tube hereafter, and allowed to settle down overnight. The volumes ofthe aqueous phase (if present), emulsion (IFC), and organic phase (ifpresent) were recorded prior to shaking the content with a vortexgenerator for 2 minutes. These volumes were taken as the initial phasevolumes. A predetermined mass of polyHIPE material was then added intothe tube and shaken for a further 2 minutes. Following the finalshaking, the volumes of the three phases were recorded at predeterminedintervals over a time period until a measured separation curve reached aplateau. These volumes were taken as the final phase volumes. Theinitial and the final values were used in to calculate a demulsificationcapacity, D, defined as:

$D = \frac{\lfloor V_{aq} \rfloor_{l} - \lfloor V_{aq} \rfloor_{i}}{\lbrack M_{PHP} \rbrack}$where V_(aq) is the volume of the aqueous phase and M_(PHP) the mass ofthe PHP particles. Indices i and I denote initial and final,respectively. The reason for using the volume of the aqueous phase incalculating the demulsification capacity is that it is easier todetermine more accurately than those of the IFC phase, which most of thetime contains the polyHIPE particles as well as the organic phase.

Samples of raw IFC and those of remaining IFC after demulsification wereanalysed by a scanning electron microscope equipped with an energydispersive analysis with x-ray (EDAX) instrument (Oxford ISIS system).Some of the polyHIPE particles were removed from the test tubes and weresubjected to the same analysis. Some demulsification tests wereperformed with the remaining IFC from the first demulsification tests.Again both the IFC and polyHIPE particles were analysed by SEM/EDAX. Thesamples of the IFC and the polyHIPE particles used in SEM/EDAX analysiswere prepared by drying them in an oven at 60° C. until all the liquidcontents were removed.

Experiments have been conducted to clean the degraded solvent as well asthe spent aqueous phase by using different types of polyHIPE materialsand some other commercially available ion exchange resins and adsorbents(for a list see Table 2). Predetermined volumes of the degraded solventand the spent aqueous phases were taken into separate test tubes towhich were then added predetermined amounts of the cleaning agents. Thetubes were shaken for predetermined periods of time and then wereallowed to rest for predetermined periods of time. When all the solidshad sedimented to the bottom of the tubes, liquids in the tubes wereanalysed visually with respect to their colours in comparison to theircolours at the start. Aliquots of the liquid phases were chemicallyanalysed for their heavy metal (mainly Pd), —COOH and TOC contents.

Both rigid and elastic polyHIPE materials were prepared and a typicalmicrograph for a rigid polyHIPE is shown in FIG. 1. This figure showsthe cellular structure of the polyHIPE material with the main cellsinterconnected by smaller windows in the cell walls. SulphonatedpolyHIPE materials have been prepared with varying degrees of thesulphonation. Table 3 summarises the results of the sulphonation tests.The degree of the sulphonation seems to be a function of the particlesize of the polyHIPE material, the temperature and the time.Sulphonation degrees of as high as 96% could be obtained by changingthese factors. FIG. 2 shows a micrograph of a typical sulphonatedpolyHIPE material. It can be seen that during sulphonation, the polyHIPEstructure is etched by the acid. This leads to the enlargement of theexisting pores and formation of new smaller pores within the cell walls.

Rigid polyHIPE cubes were soaked in IFC for two days under no externalforce or pressure. These polyHIPE samples were analysed by SEM. Themicrographs indicated that IFC penetrated into the pores of the polyHIPEmaterial and that the material was capable of retaining the solidparticles and possibly also surface active dissolved degradationproducts. Some typical micrographs are shown in FIGS. 3 a and 3 b.

Test tube demulsification tests with rigid hydrophobic polyHIPEparticles of size 1000 μm+250 μm demonstrated that polyHIPE couldsuccessfully break down IFC. Some typical results for a typical IFC typeare shown in Table 4 as well as in FIG. 4.

The results may be summarised as (M_(pHp): mass of PHP in grams andV_(T): the starting volume of raw IFC in cm³ taken into the tubes):

-   -   For M_(PHP)/V_(T)≅0.07 no separation occurs.    -   For 0.07≦M_(PHP)/V_(T)<0.12 insignificant separation takes        place.    -   For M_(PHP)/V_(T)≧0.12 significant separation occurs.    -   No organic phase remains for M_(PHP)/V_(T) above 0.15.

For M_(PHP)/V_(T)=0.15, the contents of a few tubes was taken into aseparation funnel and the drainage from the funnel under gravity wascollected in measuring cylinders. It was observed that no organic phasewas released from the cellular structure of polyHIPE and all the liquidsin which polyHIPE particles were suspended at the top were indeedaqueous phase. When a vacuum was applied, a small volume of organicphase with respect to that of the aqueous phase was also released. For aparticular test with a different type of IFC of 18 ml volume mixed with1.0 g polyHIPE, the volumes of the three phases, namely aqueous,organic, and solid (polyHIPE and absorbed material) were measured as 10ml (56%), 1.5 ml (8%), and 6.5 ml (36%), respectively. This isschematically shown in FIG. 5 in comparison to the separationperformance of sulphonated polyHIPE and that of a membrane of 0.45 μmpore size. It is clear from the figure that only 27% of the availableorganic phase (1.5 ml out of 5.5 ml) is released from the cellularstructure of polyHIPE under relatively low vacuum. It is expected that,if the level of the vacuum on the drain side of the funnel (or thepressure on the funnel side) is increased further, it may be possible toextract all of the available organic phase. This may also be achieved bya combined press-filter device.

Some polyHIPE pieces used in the demulsification was removed from thefunnel and washed with ethanol followed by water. After drying they wereanalysed by SEM and a typical micrograph is shown in FIG. 6. Incomparison to deposits displayed by the micrograph in FIG. 3, there isvery little deposit in the cells of the polyHIPE shown in the micrographof FIG. 6. This indicates that it may be possible to regenerate polyHIPEby a suitable and cheap solvent washing procedure. The solids may thenalso be separated from wash liquids by a suitable method.

Test tube demulsification experiments with a rigid hydrophilicsulphonated sodium salt of polyHIPE chopped into particles of size 1000μm±250 μm size demonstrated that hydrophilic polyfIPE could successfullybreak down IFC. But in contrast to the hydrophobic polyHIPE, the smallerthe amount of polyHIPE material used the better the separation was. Fora particular test with 18 ml IFC mixed with 0.03 g sulphonated sodiumsalt of polyHIPE, the volumes of the three phases, namely aqueous,organic, and solid (polyHIPE and adsorbed material) were measured as 9.5ml (53%), 1.5 ml (8%), and 7 ml (39%), respectively. This isschematically shown in FIG. 5 in comparison to the separationperformance of untreated polyHIPE and that of a membrane of 0.45 μm poresize. When there was a separation, some sediments with the appearance ofpolyHIPE powders occurred in the aqueous phase. These sediments weremainly positioned at the bottom of the tubes but some remained suspendedin the aqueous phase.

The results obtained from a typical set of tests with a typical type ofIFC are shown in Table 5 as well as in FIG. 7 which can be summarisedas:

-   -   For 0.034≦M_(PHP)/V_(T)≦0.15 rigid hydrophilic polyHIPE adsorbs        everything, no separation occurs.    -   For 0.008≦M_(PHP)/V_(T)<0.034 no separation occurs, some free        organic phase remains at the top.    -   For M_(PHP)/V_(T)<0.008 separation occurs. The separation gets        better for the smaller ratios.    -   For M_(PHP)/V_(T)=0.001 significant separation occurs and it        becomes better with decreasing M_(PHP)/V_(T).

The sediments in the aqueous phase, remaining IFC, and polyHIPEparticles positioned in the IFC phase were analysed using SEM/EDAX

FIGS. 8 and 9 respectively show typical micrographs and EDAX spectrum ofthe sediments. These micrographs show that small particulate materialhas been trapped in the cellular structure of the polyHIPE whereaslarger particles have accumulated on the surface. These large particlesmay be (1) the IFC particles adsorbed by polyHIPE and sedimented withpolyHIPE, (2) and/or the IFC particles which are not adsorbed bypolyHIPE but sediment when polyHIPE demulsifies the IFC resulting information of the aqueous phase. An EDAX spectrum of the total area shownby micrograph in FIG. 8 a is given in FIG. 9 a, and that of a single IFCparticle trapped in the a polyHIPE cell is given in FIG. 9 b. These bothindicate the presence of palladium in the sediments.

FIGS. 10 a and 10 b show typical micrographs of polyHIPE particlesremaining in the IFC. It is seen from the micrographs that thesepolyHIPE particles have very little porosity so that they are not ableto adsorb IFC solids. Being lighter than the aqueous phase, they arepositioned in the remaining IFC phase after demulsification.

Some separate samples of remaining IFC solids were washed with water,ethanol, and dichloromethane followed by hexane to remove any TBP and OKresidue which may have remained on the solids and dried. These washedremaining solids were analysed by SEM/EDAX as well as by chemicalmethods for their C, H, N, Pd and P content. Some typical micrographsand X-ray spectrums are given in FIGS. 11 a and 12 a for the sampleswashed with water, FIGS. 11 b and 12 b for the samples washed withethanol and FIGS. 11 c and 12 c for the samples washed withdichloromethane and hexane. Chemical analysis results for these samesamples are given in Table 6 as well as shown in FIG. 13. As for theoriginal IFC the micrographs indicate that the remaining IFC solids arealso in the form of sharp edged disc-shaped particles. These particlesagain remain in bulk either as individual particles and/or formagglomerates. The EDAX spectra of FIG. 12 indicate the presence ofpalladium in the remaining IFC.

Some detailed demulsification tests were performed to investigate thedemulsification of the remaining IFC from the first demulsification testby using both plain polyHIPE and a sulphonated sodium salt of polyHIPE,as well as a combination of the two. In these tests both the type of IFCas well as the ratios of polyHIPE mass/IFC volume were changed. It wasobserved that the plain polyHIPE did not cause any furtherdemulsification and polyHIPE itself did not undergo any changes. Thesulphonated sodium salt of polyHIPE on the other hand seemed to beabsorbing the remaining IFC without causing any further phaseseparation. In contrast to the first demulsification, the colours of theparticles of sulphonated sodium salt of polyHIPE changed into that ofthe IFC becoming dark brownish-black coloured. These sulphonated sodiumsalt of polyHIPE particles were analysed by using SEM/EDAX. FIG. 14shows typical micrographs of these sulphonated sodium salt of polyHIPEparticles. It is seen that the cell walls and pores of these sulphonatedsodium salt of polyHIPE particles have heavily been plastered by veryfine IFC solids which appear to be smaller than those absorbedinitially. Furthermore, these particles are more rounded, probablyindicating the presence amorphous organics. These results indicates thatthe polyHIPE is capable of partially demulsifying IFC by removing onlycertain agents stabilising the IFC. Other means may have to be developedfor the demulsification of the remaining IFC following the first partialdemulsification by the sulphonated sodium salt of polyHIPE.

Some very fine particles from IFC remained on the top of the polyHIPElayer in the organic phase after re-demulsification. These fineparticles were easily dispersed into the solvent phase with slightmovement of the tubes. They were also analysed by using SEM/EDAX andtypical micrographs and EDAX spectra are shown in FIGS. 15 and 16,respectively. Micrographs show that the disk-like shape of the originalIFC particles are not observed here and that the fine IFC particlesagglomerate into round-edged larger particles. FIG. 16 a shows anenhanced P peak with respect to that of the Pd. FIG. 16 b shows markedlylow Pd and P peaks but a pronounced sodium peak indicating that it ismainly an organic material. An EDAX spectrum of the total area of themicrograph in FIG. 15 a (i.e. FIG. 16 a) shows the presence of a largequantity of palladium whereas the spectrum of the bright area in thesame micrograph (i.e. FIG. 16 b) indicates very little palladium. Thespectrum of the dark region of the micrograph also showed a largequantity of palladium but less sodium than that of the total area. Thisand the bright white colour may indicate that the IFC is not only formedfrom palladium complexes of the degradation products but contains othercomponents. Therefore, the solids in IFC may be in fact two typesdifferentiated by the presence of the organics.

Effect of the particle size of the sulphonated sodium salt of polyHIPEon the demulsification was investigated for M_(PHP)/V_(T)=2.34 mg/l. Theresults are shown in Table 7.

It appears that the larger particles perform slightly better than thesmaller particles. The amount of the sediments in the aqueous phaseseemed to be the same size for all the polyHIPE particle fractions beinginvestigated and they had the same appearance. The total amount ofsediments and the amount of the suspended sediments got smaller withdecreasing particle size. This observation indicated that the sedimentsmight have not been only the polyHIPE particles but rather a mixture ofthe polyHIPE particles with solid products of the demulsification. Thiswas checked by mixing the same amount of polyHIPE particles as abovewith a mixture of aqueous (15 ml) and organic phase (15 ml) only. It wasobserved that as soon as the polyHIPE particles came into contact withthe liquid in the tube they started crumbling into much smallerparticles as a result of differential swelling which induces internalstresses. These polyHIPE particles and those sedimented after thedemulsification had the same appearance showing that the sediments werepolyHIPE particles. In contrast to the sediments after thedemulsification, the smaller particles here were positioned at the topof the aqueous phase. The reason for the particle sedimentation to thebottom of the tubes following the demulsification is that they becomeheavier as they bind the IFC solids in their cellular structure.

The degree of the sulphonation of the polyHIPE represents itshydrophilic characteristics. The effect of the degree of thesulphonation on the demulsification was investigated with sulphonatedsodium salt of polyHIPE particles of size 1000±250 μm size for varyingtypes of IFC and the ratio of M_(PHP)/V_(T) (in gram/l). For a typicaltype of IFC results are shown in Table 8. It appears that the degree ofthe sulphonation is important in the demulsification and thatdemulsification performance increases with increasing the degree ofsulphonation up to a certain point beyond which the demulsificationcapacity remains unchanged with increasing degree of sulphonation. Thisdata is shown in graph form in FIG. 17 (triangular symbol). Some moretests on the effect of the sulphonation degree have been performed for adifferent type of IFC and varying M_(PHP)/V_(T). The results are givenin Tables 9 and 10 as well as shown in FIG. 17. It seems that thedemulsification capacity of a sulphonated polyHIPE with a given degreeof sulphonation varies depending on the type of IFC. As the degree ofthe sulphonation becomes greater, polyHIPE becomes more hydrophilic incharacter and it holds a greater volume of aqueous phase in its cellularstructure. Thus in effect a lesser amount of free aqueous phaseseparates and the separation capacity is decreased with increasing ratioof M_(PHP)/V_(T).

The effect of neutralisation of the sulphonated polyHIPE ondemulsification was investigated for different degree of thesulphonation with sulphonated sodium. salt of polyHIPE particles of size1000±250 μm size and M_(S-PHP-Na)/V_(T)=mg/l. The results are shown inTable 11. The effect of the neutralisation can be evaluated by comparingthe values of demulsification capacity (D) in this table, with that ofsulphonated polyHIPE in Table 8. A careful inspection of these tablesindicates that neutralisation does not significantly influence thedemulsification performance of the sulphonated polyHIPE.

The effect of the time passed from the first mixing and the subsequentmixings during this time period have been investigated for varyingsulphonated sodium salt of polyHIPE mass (M_(PHP)/). The results areshown in FIG. 18. It is seen from the figure that at first forM_(PHP)=0.03 g no separation occurs, but as the time passes it yieldsthe highest separation of all. For 0.1≧M_(PHP)/>0.03, the volume of theinitially separated aqueous phase does not change much with M_(PHP).This means that the separation capacity is higher for the smallerM_(PHP) by virtue of its definition (see the equation above). After 25days, subsequent shakings do not seem to be causing significant changesin the volumes of the separated aqueous phase for each mass of polyHIPE.It was observed that the demulsification performance for a givensulphonated sodium salt of polyHIPE changed not only depending on thetype of the IFC (FIG. 17), as in the case of non-sulphonated PHP, butalso depending on the time passed following the first mixing (FIG. 18).It seems that if a fast separation is required, then a smaller amount ofsulphonated sodium salt of polyHIPE with a higher degree of sulphonation(40-80%) performs better as shown in FIG. 19. But if the separation timeis not a concern, better separation performances can be achieved byallowing the mixture of sulphonated sodium salt of polyHIPE with asmaller degree of sulphonation and IFC to rest for longer periods. Theseresults indicate that for a maximum separation performance importantfactors are (i) characteristics of the IFC, (ii) the degree of thesulphonation, (iii) the mass of the sulphonated sodium salt of polyHIPE,and (iv) the time passed from the first contact of sulphonated sodiumsalt of polyHIPE with IFC. It is to be noted that these factors affectthe separation interactively; that is to say that they areinterdependent. The effect of a mixture of rigid hydrophilic and rigidhydrophobic polyHIPE on the

demulsification capacity has been investigated for a fixed mass ofsulphonated sodium salt of polyHIPE (0.06 g) with varying mass of rigidhydrophobic polyHIPE (0 to 1.06 g). The results are shown in FIG. 20.For the first week the addition of hydrophobic polyfIPE slightlydecreases the separation performance. But as the time passes further,for 1.06 g hydrophobic polyHIPE addition, the separation is reduceddramatically (93%) with respect to its first day separation as well asto the case of no hydrophobic polyHIPE addition. A slight improvement(11%) in the separation is observed for 0.3 g hydrophobic PHP additionin the third week with respect to the case of no hydrophobic polyHIPEaddition. The results indicate that in batch mode demulsification, amixture of rigid hydrophilic and rigid hydrophobic polyHIPE does notcause any significant improvement in the separation performance but mayyield dramatic reduction if the mass of the rigid hydrophobic polyHIPEis above a certain limit.

Elastic PHP as produced shows mainly hydrophobic and slightlyhydrophilic surface characteristics. Only a few demulsification testswith elastic PHP were performed. The results indicated that elastic PHPwas capable of yielding a demulsification capacity D=10 ml/g for aM_(PHP)/V_(T) value as small as 16.7 mg/ml which is much better than thedemulsification capacity of the rigid hydrophobic PHP(D=0.04 ml/g forM_(PHP)/V_(T)=83 mg/ml. But the performance of the elastic PHP waspoorer than that of the hydrophilic PHP for which M_(PHP)/V_(T) value assmall as 1 mg/ml yields a demulsification capacity D=533 ml/g. This isthought to be due to the fact that hydrophilicity of the elastic PHP ishigher than that of the original rigid PHP but smaller than that of thesulphonated rigid PHP.

Elastic polyHIPE particles were kept in concentrated sulphuric acid (98%by volume) overnight in an oven at 60° C. They were washed free of theacid and used in the demulsification of the IFC which gave ademulsification capacity the same as the original (see the aboveparagraph). Some of this sulphuric acid treated elastic polyHIPE wasthen kept in 2M NaOH overnight at room conditions. They were also testedfor their demulsification capacities. The results showed that they werecapable of yielding a demulsification capacity D=1 ml/g for aM_(PHP)/V_(T)=16.7 mg/ml which is ten times smaller than those of theoriginal elastic polyHIPE and its sulphonated forms.

Some simple tests on continuous mode demulsification with differentmethods have been performed by using hydrophobic polyHIPE particles: (i)passing IFC through a polyHIPE packed bed with the aid of a peristalticpump, and (ii) adding IFC to the top surface of a polyHIPE backed bed ina separation funnel and allowing it to drain under a relatively lowvacuum. Both methods seemed to be effective in causing aqueous phaseseparation. But not much solvent phase separated due to the hydrophobicsurface characteristics of the polyHIPE. For a typical test with aseparation funnel it was possible to separate 84% of all the aqueousphase present in the IFC but only 18% of that of the solvent phase.

Efforts have been made to treat the degraded solvent phase as well asthe spent aqueous phase in batch mode using test tubes. A large numberof ion exchange resins as well as some absorbents including differenttypes of polyHIPE have been tested. The results obtained are summarisedin Table 2. The results given in Table 2 cover only physicalobservations. Some of the ion-exchange resins (Amberlite IRC-718,Amberlite IRA-900) caused excellent colour clarification both in thedegraded solvent phase and in the spent aqueous phase. Some typicalresults are shown in FIG. 21. EDAX and chemical analysis of thesesamples indicated that Pd and P were reduced dramatically by theseresins both in the solvent and the aqueous phases. The ion-exchangeresins seem to be promising for the treatment of both the degradedsolvent phase and the spent aqueous phase.

TABLE 1 TOC and metal concentration in the aqueous phase afterseparation under different conditions TOC Mg Ca Description ppm ppm ppmAqueous phase only 7 604 126 Aqueous phase with demulsifier 2 574 118Aqueous phase after demulsification 28 530 109 Aqueous phase afterdemulsification and treatment 8 546 113 with hydrophobic polymer Aqueousphase separated over a period of three 203 — — months upon standingAqueous phase separated at 200 Bar after 100 hours 120 — —

TABLE 2 Summary of the performances of the materials used in IFCdemulsification, degraded solvent treatment, and spent aqueous phasetreatment. IFC Solvent Aqueous Material demulsification treatmenttreatment Cetco Europe Ltd. no phase separation no colour changes nocolour changes NT75/EA Flocculent Cetco Europe Ltd. no phase separationno colour changes no colour changes NT75/LSK-55 Amberlite no phaseseparation excellent colour excellent colour IRC-718 clarificationclarification Ion-exchange resin Amberlite no phase separation excellentcolour excellent colour IRA-900 clarification clarification Ion-exchangeresin Amberlite no phase separation colour clarification very goodcolour IRC-400(CI) clarification Ion-exchange resin Dovex no phaseseparation no colour changes no colour changes 50WX2-100 Ion-exchangeresin Dovex no phase separation colour clarification colourclarification 1WX2-100 Ion-exchange resin Crosfield Textile no phaseseparation colour clarification colour clarification Chemicals MacrosorbCT100 Paroxite Absorbents no phase separation no colour changes nocolour changes J-550 Paroxite Absorbents Aqueous:  2 ml no colourchanges no colour changes J-500 Solvent:  0 ml Initial IFC: 22 mlParoxite Absorbents Aqueous: 14 ml no colour changes no colour changesA-200 Solvent:  0 ml Initial IFC: 22 ml Hydrophilic PHP Aqueous: 16 mlno colour changes no colour changes (S—PHP—Na) Solvent:  0 ml InitialIFC: 22 ml Hydrophobic PHP Aqueous: 12 ml no colour changes no colourchanges (PHP) Solvent:  0 ml Initial IFC: 22 ml Elastic PHP Aqueous:  5ml no colour changes no colour changes (EPHP) Solvent:  0 ml InitialIFC: 22 ml Carbonated PHP no phase separation no colour changes nocolour changes Activated Carbon no phase separation colour clarificationcolour clarification

TABLE 3 Summary of the sulphonation test. Particle size Temperature TimeDegree of (mm) (° C.) (hrs) sulphonation (%)  −1 + 0.25 40 2 10  −1 +0.25 40 4 10  −1 + 0.25 40 23 10 −3* + 1 40 4 19  5* 95 24 96  5* 95 189  5* 95 0.5 80 10* 75 and 95 3 at 75° C. and 92 8 at 95° C. 20* 95 1692 20* room 18 12 20* 95 6 86 20* 95 3.5 70 *Approximate

TABLE 4 Demulsification performance of rigid hydrophobic PHP. Raw crudvolume, V_(T) = 30 ml, room conditions. Test M_(PHP) M_(PHP)/V_(T)[V_(C)]_(i) [V_(C)]_(l) [V_(aq)]_(i) [V_(aq)]_(l) [V_(or)]_(i)[V_(or)]_(l) D No (g) (g/ml) (ml) (ml) (ml) (ml) (ml) (ml) (ml/g) 1 0.00.0000 23.0 23.0 0.0 0.0 7.0 7 0.000 2 0.5 0.0167 24.0 26.5 0.0 0.0 6.05.0 0.000 3 1.0 0.0334 22.0 26.5 0.0 0.0 8.0 5.5 0.000 4 1.5 0.0500 21.526.7 0.0 0.0 8.5 5.8 0.000 5 2.0 0.0667 21.0 27.5 0.0 0.0 9.0 4.6 0.0006 2.5 0.0834 20.0 28.8 0.0 0.1 10.0 3.3 0.040 7 3.0 0.1000 21.0 30.0 0.00.2 9.0 2.5 0.067 8 3.5 0.1167 21.5 28.7 0.0 3.0 8.5 1.7 0.857 9 4.00.1334 22.0 22.5 0.0 11.7 8.0 0.4 2.925 10 4.5 0.1500 22.0 23.7 0.0 11.78.0 0.0 2.600

TABLE 5 Demulsification performance of rigid hydrophilic PHP. Raw crudvolume, V_(T) = 30 ml, room conditions. Test M_(PHP) M_(PHP)/V_(T)[V_(C)]_(i) [V_(C)]_(l) [V_(aq)]_(i) [V_(aq)]_(l) [V_(or)]_(i)[V_(or)]_(l) D No (g) (g/ml) (ml) (ml) (ml) (ml) (ml) (ml) (ml/g) 1 0.000.000 22.0 23 0.0 0 8.0 7 0 2 0.03 0.001 22.0 6 0.0 16 8.0 8 533 3 0.080.003 22.5 10 0.0 15 7.5 5 188 4 0.12 0.004 22.0 15 0.0 10 8.0 5 83 50.19 0.006 22.0 20 0.0 5 8.0 5 26 6 0.25 0.008 22.0 22 0.0 0 8.0 8 0 70.50 0.017 22.0 28 0.0 0 8.0 2 0 8 1.00 0.034 22.0 30 0.0 0 8.0 0 0 92.00 0.067 22.0 30 0.0 0 8.0 0 0 10 4.50 0.150 22.0 30 0.0 0 8.0 0 0

TABLE 6 Chemical analysis of the solids of a typical IFC. MSOC: MembraneSeparated Original Crud, DCMWOC: Dicholoromethane Washed Original Crud,EWOC: Ethanol Washed Original Crud, WWRC: Water Washed Remaining Crud,DCMWRC: Dicholoromethane Washed Remaining Crud, EWRC: Ethanol WashedRemaining Crud. Concentration (%) REMAINING CRUD AFTER ORIGINAL CRUDDEMULSIFICATION BY PHP Element MSOC DCMWOC EWOC WWRC DCMWOC EWRC Pd19.33 35.66 37.17 18.25 22.11 21.58 P 0.58 0.07 0.10 0.62 0.38 0.38 C39.86 15.72 20.10 60.28 27.78 30.31 H 6.20 0.59 1.34 5.05 1.66 1.96 N5.82 9.44 10.79 4.10 6.69 6.06 Total 71.79 61.46 69.50 88.30 58.24 60.29Others 28.21 38.52 30.50 11.70 41.76 39.71

TABLE 7 The effect of the particle size on the demulsification.M_(PHP)/V_(T) = 2.34 mg/ml, room conditions. D Test Particle Size[V_(C)]_(i) [V_(C)]_(l) [V_(aq)]_(i) [V_(aq)]_(l) [V_(or)]_(i)[V_(or)]_(l) (ml/ No (μm) (ml) (ml) (ml) (ml) (ml) (ml) g) 1 +1000 24 130.0 14 6 3 200 2 −1000 + 710  23 13 0.0 13 7 4 186 3 −710 + 500 23 130.0 13 7 4 186 4 −500 + 250 23 13 0.0 13 7 4 186 5 −250  23 13 0.0 12 75 171

TABLE 8 The effect of the degree of the sulphonation on the demulsifi-cation. M_(PHP)/V_(T) = 3 mg/ml, room conditions. Degree of D TestSulphonation [V_(C)]_(i) [V_(C)]_(l) ]V_(aq)]_(i) [V_(aq)]_(l)[V_(or)]_(i) [V_(or)]_(l) (ml/ No (%) (ml) (ml) (ml) (ml) (ml) (ml) g) 10 24 26 0 0 6 5 0 2 10 23 19 0 5 7 7 125 3 20 23 14 0 16 7 1 400 4 40 226 0 16 8 8 533 5 92 23 6 0 16 7 8 533 6 92 23 6 0 16 7 8 533 7 92 23 6 016 7 8 533

TABLE 9 The effect of the degree of the sulphonation on the demulsifica-tion. M_(PHP)/V_(T) = 3 mg/ml, room conditions. Oct. 27, 1998 CrudDegree of D Test Sulphonation [V_(C)]_(i) [V_(C)]_(i) [V_(aq)]_(i)[V_(aq)]_(l) ]V_(or)]_(i) [V_(or)]_(l) (ml/ No (%) (ml) (ml) (ml) (ml)(ml) (ml) g) 1 0 17 18 0 0 3 2 0 2 10 17 10 0 7 3 3 108 3 20 17 8 0 7.53 4.5 115 4 40 17 11.5 0 7.5 3 2 115 5 70 17 10 0 7.5 3 3 115 6 80 17 100 6.5 3 3.5 100 7 92 17 14 0 2.0 3 4 31

TABLE 10 The effect of the degree of the sulphonation on thedemulsifica- tion. M_(PHP)/V_(T) = 4 mg/ml, room conditions. Oct. 27,1998 Crud Degree of D Test Sulphonation [V_(C)]_(i) [V_(C)]_(l)[V_(aq)]_(i) [V_(aq)]_(l) [V_(or)]_(i) [V_(or)]_(l) (ml/ No (%) (ml)(ml) (ml) (ml) (ml) (ml) g) 1 0 17 18 0 0 3 2 0 2 10 17 10 0 8 3 2 100 320 17 9 0 9.5 3 1.5 119 4 40 17 10.5 0 6.5 3 3.5 81 5 70 17 17 0 1 3 213 6 80 17 16 0 2 3 2 25 7 92 17 16 0 1 3 3 13

TABLE 11 The effect of the neutralisation of the sulphonated PHP on thedemulsification. M_(PHP)/V_(T) = 3 mg/ml, room conditions. Degree of DTest Sulphonation [V_(C)]_(i) [V_(C)]_(l) [V_(aq)]_(i) [V_(aq)]_(l)[V_(or)]_(i) [V_(or)]_(l) (ml/ No (%) (ml) (ml) (ml) (ml) (ml) (ml) g) 10 24 26 0 0 6 5 0 2 10 22 17 0 5 8 8 125 3 20 22 12 0 15 8 3 375 4 40 226 0 16 8 8 533

1. A method of demulsifying and/or separating an oil/water emulsion,comprising the steps of: i) supplying the emulsion to a rotating surfaceof a rotating surface reactor; ii) operating the rotating surfacereactor so that the rotating surface spins at a speed sufficient tocause the emulsion to spread over the rotating surface as a continuouslyflowing thin film; iii) contacting the emulsion on the rotating surfacewith a polymerised High Internal Phase Emulsion (polyHIPE) materialhaving a microcellular highly porous structure so as to causedemulsification and/or separation of the emulsion and wherein thepolyHIPE material is in powder or granular form.
 2. A method accordingto claim 1, wherein the oil/water emulsion is a crude oil emulsion.
 3. Amethod according to claim 1, wherein the oil/water emulsion isinterfacial crud (IFC).
 4. A method according to claim 1, wherein thepolyHIPE material is a rigid polyHIPE material.
 5. A method according toclaim 1, wherein the polyHIPE material is an elastic polyHIPE material.6. A method according to claim 1, wherein the polyHIPE material is ahydrophobic polyHIPE material.
 7. A method according to claim 1, whereinthe polyHIPE material is a hydrophilic polyHIPE material.
 8. A methodaccording to claim 1, wherein the polyHIPE material is a sulphonatedpolyHIPE material.
 9. A method according to claim 1, wherein thepolyHIPE material is a sulphonated alkali salt of a polyHIPE material.10. A method according to claim 1, wherein the polyHIPE material is asulphonated sodium salt of a polyHIPE material.
 11. A method accordingto claim 1, wherein the polyHIPE material is recovered and recycledafter separation and/or demulsification of the oil/water emulsion.